It’s a move consumer advocates say has been needed for a long time: This morning, the Consumer Financial Protection Bureau announced that it will start supervising large credit reporting agencies — the first time these companies have ever been subject to such oversight at the federal level.

These companies, including Experian, Equifax and TransUnion, are vast data repositories that hold the key to Americans’ ability to get a loan, get decent borrowing rates and sometimes even get a job. These quote-unquote Big Three bureaus have files on 200 million of us and collectively crank out around 3 billion reports each year. If they make a mistake, the cost to that individual potentially can be enormous.

The credit reporting industry says only around 1% of credit files contain errors that can negatively impact a person’s financial status. Consumer watchdog groups point out that even if this number is accurate, that’s still 2 million people — and they point to studies of their own that draw very different conclusions. One study conducted by the National Association of State Public Interest Research Groups says as many as 79% of files contain mistakes, and 25% have what it calls “serious errors” that could keep people from being able to obtain credit.

While the Big Three bureaus are the ones most people know about, there are actually a staggering 400 or so consumer reporting agencies that collect Americans’ data. The CFPB’s authority covers roughly 30 of the biggest bureaus, which account for 94% of the market. In addition, it also put together a Q&A for people on its website that answers common questions about credit reports.

Chi Chi Wu, staff attorney at National Consumer Law Center, says in a statement that any steps the CFPB takes to improve the accuracy of the information in people’s credit files and make the bureaus more responsive in disputes with consumers “could potentially improve the economic lives of millions of Americans.” The NCLC slams the current dispute process bureaus use to resolve consumer complaints, calling it “automated and perfunctory.”

Previously, the Federal Trade Commission had law enforcement authority over credit bureaus, which meant it had to wait until a company broke a law before it could take any action. The CFPB’s supervision will be proactive and will require the bureaus to submit to compliance reviews, allow examinations and provide the agency with reports at its request. The rule giving the CFPB this supervisory authority kicks in September 30, and the agency will begin examining the credit bureaus after that. For anyone who’s experienced heartburn trying to get a credit report error resolved, this is a light at the end of the tunnel.